PROJECT SUMMARY/ABSTRACT Suicide is a leading cause of death, with over 47,000 individuals who die by suicide each year in the United States. Nonfatal suicidal thoughts and behaviors (STBs) not only confer risk for future death by suicide, but also are associated with significant public health and economic costs, and extremely distressing to those who experience them. Though a number of in-person psychotherapy protocols have been developed or modified to address STBs, some of which have shown promising results, many individuals in need are unable to access such treatments. Barriers to accessing face-to-face psychotherapy include cost, difficulties with scheduling, distance from qualified providers, long waitlists, and perceived stigma. The fact that the suicide rate has not yet declined (and for some subsets of the population, has increased steadily) suggests that many suicidal individuals are not receiving the more promising existing interventions. Telehealth, which facilitates delivery of evidence-based therapeutic content over videoconferencing technology or telephone sessions, may help overcome the barriers to accessing treatment and thus help suicidal individuals receive the care they need, including during particularly high-risk time periods. Yet, to our knowledge, telehealth has not yet been systematically leveraged to improve access to evidence-based psychotherapy for recently discharged suicidal inpatients. This supplement proposes a telehealth adaptation of the intervention being tested in R34MH113757, which involves three brief in-person skills training sessions during suicidal individuals? inpatient stays followed by a smartphone-based ecological momentary intervention (EMI) aimed to facilitate skills practice during real-world moments of distress over the 28 days after discharge: the highest-risk period for suicidal behavior. Specifically, we will evaluate delivery of in-person skills training sessions over telehealth in two ways: (1) as a supplement to the in-person session(s) that participants are able to receive before being discharged, and (2) as a standalone intervention in which participants receive all three sessions via telehealth after discharge. This novel adaptation has the potential to vastly improve R34 study feasibility (as almost half of participants in the pilot study have been unable to receive all three sessions before being discharged due to clinical or scheduling issues) and possibly, intervention efficacy (due to slowing the pace of skills delivery and thus potentially improving skills acquisition and consolidation). We will test hypotheses that the telehealth - delivered sessions will be both acceptable (from participants? and therapists? perspectives) and feasible, in that, for example, telehealth will maximize the number of sessions participants receive in total and improve compliance to the EMI after discharge. We will also preliminarily evaluate the efficacy of telehealth-delivered sessions in terms of changes in momentary suicidal ideation before and after using the EMI for skills practice. This supplement has the potential to not only improve the potential knowledge gleaned from the parent R34, but also the understanding of scalable intervention modalities for patients at risk for suicide on a large scale.